Insulating behavior of alkali-metal-covered GaAs(110).

Abstract

A combined effort of local density approximation (LDA) and many-body calculations is aimed at an understanding of the nature of the insulating behavior of GaAs(110) under submonolayer alkali-metal coverage. In particular, a Hubbard model is constructed with its parameters extracted from LDA pseudopotential calculations. The electron hopping spectrum is calculated using an exact diagonalization technique. The combined LDA and many-body results demonstrate that the GaAs(110) under submonolayer alkali-metal coverage up to {theta}=0.25 is a Mott-Hubbard insulator. {copyright} {ital 1996 The American Physical Society.}